The placenta, a female reproductive organ responsible for feeding, removing waste, and providing oxygen to a fetus, also allows transfer of antibodies from mother to child in order to help prevent infection. Because of the latter function, it was believed that children got their first dose of bacteria while during vaginal birth (or skin-to-skin contact if delivered by C-section), not inside the womb. However, researchers have learned that this isn’t the case: Babies have bacteria in their gut when they’re born and these bacteria don’t match those in the vagina.

Fetal medicine specialist Kjersti Aagaard of Baylor College of Medicine wanted to find the source of the bacteria. She, along with a team of researchers, analyzed the bacteria in the placentae of 320 women. In place of evaluating the bacteria under a microscope, Aagaard opted to sequence the DNA of the bacteria.

With the genetic makeup of the placenta bacteria identified, the team compared it to the DNA of microbes found in the mouth, nose, skin, vagina and gut of non-pregnant women. What they found was that placenta bacteria resembled bacteria found in the mouth much more than other areas of the body. And while the process has not been identified, Aargaard reasons that oral bacteria can enter the bloodstream in the mouth and travel to the placenta.

So, what does this mean? Aargaard believes this “reemphasizes the importance of good oral health” during pregnancy. While more research needs to be done to confirm the results of this study, it is important to accept that your mouth has a deep connection to processes of your body, including pregnancy.

If you have dental insurance, make sure to check if it offers a third cleaning benefit. This will allow you to visit the dentist for a cleaning three times in a calendar year if you are pregnant. Ideally, your first check-up and cleaning should be within the first trimester.